Predictive value of serum d-serine level for hearing impairment in uremic patients

Figures & data

Table 1. Comparison of basic conditions of the two groups of uremia patients.

Item		Normal hearing samples (n (%))	HI samples (n (%))	p
Gender	Male	15 (50.0)	22 (73.3)	.063
	Female	15 (50.0)	8 (26.7)
Diabetes	No	27 (90.0)	24 (80.0)	.472
	Yes	3 (10.0)	6 (20.0)
Hypertension	No	0 (0.0)	0 (0.0)
	Yes	30 (100.0)	30 (100.0)
Renal anemia	No	12 (40.0)	15 (50.0)	.436
	Yes	18 (60.0)	15 (50.0)
ALB (40–55 g/L)	≥35	29 (96.7)	27 (90.0)	.612
	<35	1 (3.3)	3 (10.0)
Potassium (3.5–5.3 mmol/L)	<5.3	15 (50.0)	19 (63.3)	.297
	≥5.3	15 (50.0)	11 (36.7)
Calcium (2.11–2.52 mmol/L)	<2.52	26 (86.7)	27 (90.0)	1.00
	≥2.52	4 (13.3)	3 (10.0)
Phosphorus (0.85–1.51 mmol/L)	<1.51	2 (6.7)	4 (13.3)	.671
	≥1.51	28 (93.3)	26 (86.7)
BMI (kg/m^2)	Thin	6 (20.0)	3 (10.0)	.637
	Normal	14 (46.7)	18 (60.0)
	Overweight	7 (23.3)	7 (23.3)
	Obesity	3 (10.0)	2 (6.7)
Central obesity	No	15 (50.0)	11 (36.7)	.435
	Yes	15 (50.0)	19 (63.3)
UA (male: 208–428 μmol/L; female: 155–357 μmol/L)	Normal	6 (20.0)	4 (13.3)	.488
	Raise	24 (80.0)	26 (86.7)

HI: hearing impairment; ALB: albumin; BMI: body mass index; UA: uric acid.

Table 2. Comparison of age, renal function, PTH, and serine levels between the two groups.

Item	Normal hearing (n = 30)	HI (n = 30)	t	p
Age (years)	40.73 ± 9.24	46.67 ± 10.93	–2.271	.027
BUN (mmol/L)	28.83 ± 6.58	28.38 ± 7.65	0.246	.807
Cre (μmol/L)	1179.00 ± 289.28	1104.41 ± 290.44	0.997	.323
PTH (pg/mL)	609.71 ± 468.27	634.57 ± 657.44	–0.169	.867
d-Serine (μM)	9.09 ± 2.71	12.27 ± 2.18	–5.003	<.001
l-Serine (μM)	11.81 ± 4.40	9.20 ± 5.33	2.068	.043

BUN: blood urea nitrogen; Cre: creatinine; PTH: parathyroid hormone.

Reference range: BUN 3.6–9.5 mmol/L (male), 2.6–7.5 mmol/L (female); Cre 57–111 μmol/L (male), 41–73 μmol/L (female); PTH: 12–88 pg/mL.

Table 3. Multiple logistic regression analysis results of HI in uremia patients.

Item	B	S.E.	Wald	p	OR	OR (95% CI)
Age	2.089	0.767	7.420	.006	8.081	1.797–36.337
d-Serine	2.013	0.773	6.775	.009	7.482	1.644–34.054
l-Serine	–1.548	0.659	5.517	.019	0.213	0.058–0.774
Constant	–1.485	0.864	2.953	.086	0.227

HI: hearing impairment.

Figure 1. ROC curves of age, d-serine, and l-serine for diagnosing HI in uremic patients.

Figure 2. ROC curve of d-serine in the diagnosis of HI in uremic patients.

Figure 3. ROC curve of age in the diagnosis of HI in uremic patients.

Figure 4. ROC curve of 1/l-serine in the diagnosis of HI in uremic patients.